Interleukin 10 (IL10) was identified as a cytokine synthesis inhibition factor, exerting effects on Th1 helper cells and antigen presenting cells (APC's). IL10, a 161 amino acid protein that exists as a domain-swapped non-covalent homodimer, binds to the high affinity IL-10 receptor I (IL-10RI) with a stoichiometry of one homodimer to four IL-10RI subunits that recruits IL-10R2 and activates signal transduction through JAKI/TYK2 pathway. IL10 inhibits monocyte and macrophage synthesis of pro-inflammatory cytokines, e.g., IL-1, IL-6, IL-8, IL-12, TNF-alpha, GM-CSF, and reactive oxygen and nitrogen intermediates, and has shown strong efficacy in numerous preclinical models of autoimmunity. IL10 efficacy is thought to result from its ability to inhibit activation and effector function of monocytes, macrophages, and T cells. However, IL10 is a pleiotropic immunoregulatory cytokine with a very broad spectrum of biological activities. IL10 has also been shown to promote growth and differentiation of B cells, NK cells, cytotoxic and helper T cells, mast cells, granulocytes, dendritic cells, keratinocytes, and even endothelial cells, indicating it also possesses pro-inflammatory functions (Moore et al., Annu Rev Immunol. 2001; 19:683-765).
IL10 as a therapeutic for the treatment of autoimmune and inflammatory conditions, specifically inflammatory bowel disease (IBD), is supported in animal model systems as well as genetics. For example, knockout of IL10 in mice and mice with a defect in the IL-10R develop a spontaneous onset of colitis. In humans, 9-16% of Crohn's Disease patients have a NOD2 mutation that is associated with defective or reduced IL10 production, and 20% of ulcerative colitis (UC) patients carry a disease-associated IL10 SNP in the 3′UTR. Lastly, certain mutations in IL-10R1 in humans cause a rare, severe form of Crohn's Disease (Glocker at al., N Engl J Med. 2009; 361(21):2033-45).
Despite the strong genetic linkage data, recombinant human IL10 demonstrated tolerability and safety in healthy volunteers and specific patient populations up to 25 μg/kg, and mild effects in a subset of recipients up to 100 μg/kg; however only mild clinical efficacy was found for the specific patient populations and clinical development was discontinued for lack of efficacy. Reviews of the studies have been undertaken and several possibilities for the results have been identified, for example, limited efficacy is due to poor exposure of the target organ (colon) due to short half-life of IL10; the pro-inflammatory effects of IL10 that manifested at high doses and counterbalanced the anti-inflammatory efficacy of low dose IL10. (Lindsay and Hodgson, Aliment Pharmacol Ther. 2001; 15(11) 1709-1716) Consistent with this possibility, high doses of IL10 were associated with elevated systemic IFNγ, granzyme and neopterin levels, which are associated with increased inflammation (Tilg et al., Gut 2002; 50(2)191-5).
Antibody cytokine engrafted proteins have been developed to generate a more effective IL10 therapeutic that confers an improved profile that address the clinical failings of recombinant human IL10. This improved therapeutic profile includes strong anti-inflammatory IL10 potency with a marked reduction in pro-inflammatory activity, extended half-life, ease of administration and stability. Thus, the disclosure provides improved IL10 antibody cytokine engrafted proteins and methods of treating immune related disorders.